Method of making cotton spun yarn



June 18, 1940. FARRELL I 2,205,286

METHOD OF MAKING COTTON SPUN YARN Filed Nov. 15, 1939 Jame E. Farrell INVENTOR.

. BY I ATTORNEY Patented June 18, 1940 METHOD OF MAKING COTION SPUN YARN James E. Farrell, Boylston, Ala., assignor to West Boylston Mfg. Company of Alabama, a corporation of Alabama Application November 15, 1939, Serial No. 304,465

. 5 Claims.

The invention relates to cotton spun yarn, particularly such as used in the manufacture of cord for automobile tires, belting, and the like, where tensile strength, elasticity, and flexibility are specially important. The object of the invention is to provide a new and valuable spun yarn having as nearly as possible a minimum of fibre elongation and of,unnec essary fibre tension, as nearly as may be perfect elasticity, and great tensile strength when made into cord. A further object is to provide a method for making such spun yarn.

The basis of the invention is the utilization of cotton fibres which have a substantial excess of spirality in one direction--and fibres without such excess cannot be employed in the invention-in such manner as to reducethe tension and elongation of the fibres in the spun yarn to an extent approximately overned by the amount of such excess of spirality. In forming spun yarns pursuant to the method the fibres are so spun together that the turns of the excess of natural spirality of the fibres are pulled out, deformed, or unwound against the elastic force of such turns tending to maintain their original form. The result is that as the fibres are twisted into the spunyarn with any specified number of twists per unit of length, of the machine, or as counted in the spun yarn, the individual fibres are substantially less elongated, and substantially less subjected to tensile strain, than would be the case if said fibres lacked such excess of spirality; for in the deformation of the turns of such excess a substantial elongation is had before the fibre is stretched-the turns being merely pulled out.

In the drawing, the figure is a mere elementary diagram showing fibres I, 2, 3, being twisted into a spun yarn 4, and the curved arrows 5 and 6 indicate the direction of twist used in forming the spun yarn; which direction will be that which will pull open, deform, and unwind any excess of natural spirality in the fibre.

As indicated the invention cannot be carried into effect with fibres lacking an excess of natural spirality in one direction, and the greater this .excess the better the spun yarn made under this method. 7

The spirality of cotton fibres is by no means the same in cotton of various geographical origin; nor is every cotton with great natural spirality valuable in the invention. The cotton which can be employed to best advantage in one with a fibre in which there is a substantial ex-, cess of natural spirality in one direction, that is direction that it can be spun pursuant to the in-' vention advantageously; in the spinning process, provided the direction of spinning be that which will pull out, deform, or unwind the turns of such excess, the fibres will be by no means as much elongated, and by no means as much subjected to tensile strain, as would be the case without such excess. For in the spinning process the effective increase in length of the fibres as they take position in the spunyarn is largely reached by the pulling out, deformation, and unwinding of the excess turns. The result is a spun yarn the fibres of which have. been substantially subjected to such tensile strain as necessary to deform the excess turns of the fibre plus what may be a relatively smaller strain involved in any actual lengthening of the fibre itself. It should be understood that much less tensile strain is involved in elongating the spiral of the fibre than in stretching the fibre itself. And this invention directly utilizes this diflerence in so forming the spun yarn that the fibre tension developed by this spinning process is, as substantially as possible, employed against the resilient yielding of the excess spirality rather than in the elongation of the fibre itself.

Because of the greatly reduced elongation of fibres, and the greatly reduced tensile strain on the fibres, in the spun yarn, such spun yarn when formed into cord contributes properties of the utmost advantage. Heretofore cotton tire cord of standard weight and gauge as here contemplated has had ultimate tensile strength of about fifteen pounds; it has had flexibility to such extent as existing methods permitted; and it has lacked considerably anything like perfect elasticity, as shown by the well developed knees in testing machine graphs made under standard conditions. On the other hand a cord made up from spun yarn formed pursuant to this invention, and for some time such cord has been manufactured and used in quantity, shows an ultimate tensile strength of from seventeen and one-half to more than nineteen pounds, with almost a straight-line graph-indicating nearly perfect elasticity and uniform elongation per unit of stress-in repeated tests by standard apparatus as utilized by cord manufacturers. Also, tires made with such cord, the spun yarns of which were formed pursuant to this invention, have stood up under mileage tests for more than forty thousand miles, which obviously indicates great flexibility.

These very material qualities of the cord made from spun yarn formed pursuant to the invention appear to be due to the excellence of the spun yarn, in which the fibre tension and elongation have been substantially minimized by the expedient of so spinning the fibres together as to take full advantage of the excess of natural spirality of the fibre.

Obviously, in carrying the invention into effeet I select fibres in which the excess of natural twists in one direction over those in the other direction is substantial; the greater such excess the better the fibres for my purposes. Fortunately, I find that the more expensive grades of cotton are not necessarily those most suited for the purposes of the invention. I obtain satisfactory results with ordinary grades of what is known as Uplands cotton and do not have to resort to the more expensive and long staple cottons. Doubtless, with a long staple cotton, such as Sea Island, or some other variety, possessing the necessary substantial excess of spirality in one direction, I might produce, following my invention in forming the spun yarn, a cord having even greater tensile strength and flexibility than that already mentioned, which was made of ordinary Uplands cotton.

This invention is to an extent only indicated in my application Serial Number 259,316, filed March 2, 1939, entitled Cord and method of making same, made prior to quantity production of cord with spun yarn formed as herein described. The claims herein made could not be made in that case without introducing new matter not disclosed in that application, the disclosure therein going substantially only to the production of a neutral spun yarn. Here the production of a neutral spun yarn is a mere incident; my yarns may or may not be stable; and the object here is a spun yarn in which necessary fibre tension is so greatly reduced as to preserve as far as possible the tensile strength and elasticity of the natural fibre.

This invention is not a mere matter of spinning fibres into a spun yarn with one or the other of the two possible directions of twist, both sumciently old. It contemplates-examination of the microscopically minute natural twists of the cotton fibres and the selection of such fibres in. which there is substantial preponderance of twists of one kind over twists of the other kind, and then the formation of spun yarn in such manner as to utilize to advantage these normally invisible but extremely important qualities of the fibre to produce a radical improvement in the related art.

Having described my invention what I claim is:

1. The method set forth which consists in selecting a cotton the fibres of which have a substantial excess of natural spirality in one direction, then spinning such fibres together into a spun yarn with such direction of twisting and to such extent that while the spun yarn has been given and shows a definite number of twists per unit of length a substantial portion of the twisting has merely pulled out such excess and only the remainder of the twisting has elongated the fibres.

2. The method set forth which consists in selecting a cotton the fibres of which have a substantial excess of natural spirality in one direction, then spinning such fibres together into a spun yarn with such direction of twisting and to such extent that while the spun yarn has been given and shows a definite number of twists per unit of length the fibre tension developed by such twisting has been substantially employed in pulling out the turns of such excess and employed only in part in elongating the fibres.

3. The method set forth which consists in selecting a cotton the fibres of which have a substantial excess of natural spirality in one direction, then spinning such fibres together into a spun yarn with such direction of spinning as will unwind such excess of spirality and to such extent of such unwinding that the fibre tension developed in the spinning is substantially employed in deforming the turns of such excess of spirality and only in part in elongating the fibres, substantially as set forth.

4. The method set forth which consists in selecting a cotton the fibres of which have a substantial excess of natural spirality in one direction, then spinning such fibres into a spun yarn with direction of twisting opposite that of such excess and to such extent as will substantially unwind the turns of such excess and only in part actually lengthen the fibres, substantially as set forth.

5. The method set forth which consists in forming a spun yarn from cotton fibres having a substantial excess of spirality in one direction by twisting the fibres together in a direction oppositev that of such excess, and to such extent that in the formed spun yarn the necessary increased length of the fibres consequent on their spiral disposition in the yarn is substantially due to deformation of turns of such excess. by unwinding and only in part to any actual elongation of the fibres, substantially as set forth.

JAMES E. FARRELL. 

